Erosion threatens Scroby windfarm stability

Scroby Windfarm seen from the shoreline

Scroby Windfarm seen from the shoreline

The continuing dredging of aggregate in close proximity to the Scroby wind turbines has brought about a considerable reduction to the Scroby Sandbank and loss of the seabed, to the extent that the wind turbines embedded nearby are now threatened with instability.

Three years ago the deeply entrenched power line taking the generated power from the Scroby turbines to the shore was stripped of protective cover due to sandpit demand brought about by the deepened dredged adjacent seabed area, leaving the cable dangling well above the eroded seabed leading to fracture, the repair of which was very expensive to replace. The power supply was lost until replacement resulted. This could and should have been heeded as a warning at that time. Further aggregate dredging should have been terminated then, but despite opposition to granting further dredging licences for the area, sea bed aggregate dredging continues, and each and every application for a licence to dredge is granted.

When gas lines were instituted for the North Sea platforms to the Bacton shore plant, they were deeply embedded in the ocean floor and covered with a thick layer of concrete. They have not suffered from exposure due to loss of the seabed. But then they are not close to the dredging site(s).

What at first seemed a good and relatively low cost idea and a possible solution for providing stability for the Scroby Windfarm turbines was proposed by EON and the MMO. Their proposition was to place polypropylene nets filled with rubber tyres placed at the base of the worst affected Scroby Wind Turbines to protect the base from further endangering erosion due to seabed lowering, indeed to capture more sand and gravel driven by the strong tides of the area.

In the past discarded rubber tyres have been tried as a means of sea defence at seaside resorts as a means of protecting the coastline from erosion. But there were misgivings then, in that the shoreline waves impacted the barrier by sand and gravel attack that would liberate shards of synthetic rubber which could choke the guts of fish. Furthermore, the components of such tyres are far from benign.

Using the rubber from tyres as an experimental dressing component for a road showed that leachate resulted after rain polluting the aquifer to an unacceptable level.

Mike King, Pat Gowen, Norma Gowen and many members of our Coastal and North Sea action Groups attended the Public Meeting held at the Caister-on-Sea Hotel on 10th September 2014, called by EON and the MMO, to hear from the horses mouth the plan intended, and to ask any questions and give views on using tyres in this way. An application Ref: MLA/2014/00273 was placed on the MMO website and and publicised in the local press. At first sight this application appeared quite reasonable and that it provided a degree of protection at minimal cost. It further reduced the land dumping of the mountain of discarded tyres that has been seen as contaminating the aquifer.

But a deeper study of the plan showed the practice not to be so benign as suggested at the meeting, and following further research into the issue has now led us to have grave concerns on the proposed practice.

The fishermen of the area expressed their concern through Paul Lines, the Secretary of the local fisherman’s organisation. He pointed out his own experience that polypropylene and synthetic rubber disintegrated on the seabed, and that the release of the tyres over large areas of the seabed would destroy the fishing ground.

His objection to the proposal to the MMO reads as follows:

Subject: MLA/2014/00273

Dear Tracy

I wish to place an objection for and on behalf of Great Yarmouth Inshore & District Fisherman, with whom I am secretary, and Anglia Fisherman’s Association, for whom I am Chairman, to the proposal of dumping tyres at the foundations on Scroby Sands Windfarm to prevent scour. My list of concerns/objections are as follows.

Leachate from these used tyres has not been identified that it is not a threat to the food chain. In actual fact studies have been undertaken around the world to prove that harmful materials such as zinc, cadmium, chlorinated biphenyls, butadiene, styrene, solvent benzene and polycyclic aromatic carbons to name but a few. These chemicals are toxic and carcinogenic. The reports below, and the studies that have been undertaken by various parties, all conclude that no long term effect to the marine environment is known. Bioaccumulation is a major concern to us, as the fish and shellfish that is harvested from this area, could be subject to large amounts of toxins that could enter the food chain. And thus render the food resource unusable an subject to an area closure for environmental impact assessment. Please see below publicised references for deliberation on this matter.

The Myth of Rubberized Landscapes

Physical damage to environment. The methodology in which the tyres have been loosely bound together and held in a lightly netted bag is unacceptable. Over a short period of time, the polypropylene rope and net with which these tyres are bound together will chaff away and cause an ecological disaster. Polypropylene rope will wear through from sand medium being moved in the tide, and also from the movement of the net against the static tyres. This will allow the tyres to release themselves and be subject to free movement on the seabed. This not only concerns the inshore fisherman who could possibly catch rogue tyres whilst engaged in fishing activities, and cause a vessels stability to be comprised due to the unexpected loading criteria applied, or for a drift net fisherman to lose an entire fishing ground due to obstruction and nets being fouled. but these loose tyres could be washed up on public beaches and cause a hazard to all beach users.  Please use this link to view the suitability of this variety of rope. Another concern is that none of the tyres have an identification badge or serial number. This leaves no accountability or traceability in the event of any tyres breaking free.

Tyre removal — as the supplier or any other party attempted to remove the trial bags of used tyres, how has it been shown that when the Windfarm goes into its decommissioning phase, that (if they last this long) the bags can be successfully removed. The net bags used have only been loaded with tyres, and the total weight of sand and water has not been taken into account. This trial was conducted in a skip in Ireland, which I feel is in no way similar to the actual scenario faced.

Environmental impact of tyre spillage. How is proposed to monitor these tyres and in the cause of a spillage recover/track the lost tyres. It seems very thoughtless not to have any identification on these tyres as it leaves all aspects of traceability impossible. Studies have been undertaken to show that loose tyres do and will move with the current flow along the seabed. In such a strong tidal area this leaves the whole area susceptible to being polluted in the event of a bag breaking open.

Environmental impact assessment. Has baseline data been provided to the amounts and variety of species which habit in the Scroby Sands area? ie 3 mile radius. Have any toxicology reports been made on the species that inhabit this are to identify any increases/decreases in pollutants and stock sizes?

Clean seas policy. Our fisheries organisations in this area all adopt a standard working practice of removing net and debris from the marine environment. It seems incredulous that it has now been proposed to allow more used tyres and net to be dumped at the base of a foundation, simply as it is the most cost effective approach. Do we need to risk polluting the sea more before anyone can categorically prove no ill effects to shellfish communities no long term effects of heavy metal contamination and most of all a safe stock of fish for supply to the markets fit for human consumption. It’s also a valid point that after a long hard also costly struggle for local councils to educate the community against fly tipping rubbish, you will by granting this licence give the perception its OK to dump tyres in the rivers and the sea. This will undo all the positive work that has been accomplished by conservation society’s throughout the country.

Summary — The risk of towers being compromised by scour is minimal, as admitted by Steve Johnson on the video taken at the consultation meeting at Old Hall Caister. It was calculated in the principal design that tower stability was to be achieved from piling into the clay to refusal. I was involved in this project in the autumn of 2003, 5 hours into first pile 4.5 metres of sand had scoured from around the pile. This has led me to believe that this is just a trial venture to attempt to protect the array cables from damage. The transition pieces are fitted with moveable J tubes to allow for this scour, so I see no reason why they are not utilised. We have various company’s locally and around the UK that specialise in scour and cable protection, and none of them use this unproven method of protection. I do not see why Scroby sands should be used as a petri dish to assess is this works or not. The oil and gas industry has adopted concrete mattressing as its preferred method of scour prevention, and this method has over 30 years of success. After discussing this with our members we concluded that it would be of minimal concern if the materials used in this proposal were of certified food grade standard and the securing method was of a more suitable standard. The method proposed will simply entangle marine life, and when it eventually breaks open to release the tyres into a more wider marine environment, cause issues like “ghost net fishing” which will endanger all marine life and those who seek an earning from the sea. Scroby Sands has a large seal colony, endangered Little Tern colony and is in the process of being designated a site of special scientific interest.

I trust you to judge this fairly and assess my opposition to this proposal. I represent 10 local fishing vessels and the interest of the local public.


Paul Lines, 17-19 Mill Road, Hemsby, Norfolk, NR29 4ND


MARINET responded to the MMO consultation with the following:

17 Heath Crescent,

FAO MMO – 16th September 2014

I respond to your press notice advertised application MLA/2014/00273.

Having attended, with other MARINET and North Sea Action Group members, the Caister Hall Hotel Public Meeting of 10th September 2014 and heard the advantageous claims made for placing nets of filled rubber tyres at the base of Scroby Wind Turbines to protect the base from endangering erosion due to seabed lowering, I have since researched the issue which has now led me to grave concerns on the proposed practice..

On the positive side:

(1) We are fully aware of the necessity to maintain the stability of the turbines to permit continued power generation, a vital factor in attempting
to lower the grave escalation of Carbon Dioxide. Three years ago the deeply embedded power line taking the generated power from the turbines to the shore was stripped of protective cover due to sandpit demand brought about by the deeply dredged adjacent seabed area, leaving the cable dangling well above the eroded seabed, the repair of which was very expensive to replace. The power supply was lost. This should have been heeded as a warning at that time. Further aggregate dredging should have been terminated then.

(2) We are also fully aware of the considerable loss of sand and shingle depth on the seabed and the reduction of the Scroby sandbank, also brought about by nearby offshore aggregate dredging, in the same way as this is stripping our beaches and dunes along the coastline. This main causative problem needs urgent rectification by the MMO recognising cause and effect and in doing so refusing to continue to grant further offshore aggregate licences at source as a preventative measure.

(3) We are further aware of the problems created by the growing discarded tyre problem, and the need to develop a safe and effective means to combat by environmentally acceptable recycling.

However, a serious negative side exists in prolonged tyre marine immersion, i.e. the introduction of toxins and carcinogens into the marine environment eco-system and food chain.

(a) Rubber tyres contain carcinogens, e.g. neoprene, butadiene, halogens, butyl rubber and organohalogens, which at the very least will act as pheromone disruptors, and at the worst as hormone disruptors,

(b) Rubber tyres also contain heavy metals, e.g. lead, cadmium, manganese, mercury and zinc, plus aluminium, all of which are toxic in the marine environment when exposed as the rubber tyres disintegrate.

Both (a) and (b) classes will be released as the tyres degrade in the aqueous medium, and further would be ingested by crustaceans, directly, or via barnacles, mussels, etc. then entering the food chain.

(c) The powerful tides of the area and the coarse mobile grit bombardment will create rubber shards that will be consumed by fish and so blocking the gut.

Below is an extract of a paper from the New Zealand Department for the Environment to be seen at

5. Potential Environmental Impacts of Tyre Leachate

The literature reviewed on the environmental impact of tyre leachate is summarised in Sections 5.1 and 5.2. It should be noted, however, the review was not an in-depth analysis of the literature.

5.1 Recent Laboratory Research

Recent laboratory research on tyre leachate reviewed in this study is briefly summarised in Table 5.1.

Table 5.1: Summary of reviewed laboratory research on tyre leachate

View summary of reviewed laboratory research on tyre leachate (large table)

In the laboratory tyre leachate is often generated by inundating a tyre sample (plug, shred, chip, or crumb) with water. There are limitations when comparing the results of the reviewed laboratory studies as different makes of tyres were used and different compounds were measured; however the following general observations can be made about the tyre leachate generated in the laboratory:

  • it may be toxic to some fish species (e.g. rainbow trout but not minnow)
  • bacteria, invertebrates and green algae
  • levels of aluminium and manganese are likely to be elevated, especially where steel is exposed
  • levels of mercury and lead may be elevated; however most studies reported negligible levels
  • levels of zinc and organic compounds are likely to be dependent on individual circumstances as a wide range of levels have been reported in the studies reviewed
    levels of other substances are likely to below United States Drinking Water Standards
  • levels of leachate compounds (metals and organic compounds) are likely to increase with time of inundation, increase proportionally with amount of tyre and decrease proportionally with size of tyre exposed to inundation.


We noted that the parts of your presentation only briefly mentioning the negative factors suggested that these “should not result”. This assumption is not good enough. It is essential to know that they DO NOT and WILL NOT exist.

Thus, we object to the proposal as it stands, and suggest that a long term study of at least five years be instituted on a single turbine base so that removal and inspection is possible, in order to determine if such practice is environmentally acceptable in the long term future.

Pat Gowen — MARINET & NSAG

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